Crankshaft Position Sensor: Description and Operation

Ignition Control System:

Ignition Synchronization:

Ignition Control:

OPERATION
The two crankshaft sensors are located on the front bank of the engine block between cylinders 4 and 6. Crankshaft position 'A' sensor is located in the upper crankcase and crankshaft position 'B' sensor is located in the lower crankcase. Both sensors extend into the crankcase and are sealed to the engine block with O-rings. The crankshaft position sensors are not adjustable.

The magnetic crankshaft position sensors operate similar to the pick-up coil in a distributor. When a piece of steel (called a reluctor) is repeatedly moved over the sensor, a voltage will be created by the sensor that appears to go 'ON-OFF-ON-OFF-ON-OFF'. This ON-OFF signal is also similar to the signal that a set of breaker points in a distributor would generate as the distributor shaft turned and the points opened and closed.

The reluctor ring is cast onto the crankshaft between the # 3 and # 4 main bearing journals. The reluctor ring has 24 evenly spaced notches or air gaps and an additional 8 unevenly spaced notches for a total of 32.

As the crankshaft makes one complete revolution, both the 'A' and 'B' sensors will produce 32 'ON-OFF' pulses per revolution. In addition, the 'A' sensor is positioned 27° of crankshaft revolution before the 'B' sensor. This creates a unique pattern of 'ON-OFF' pulses sent to the ignition control module so that it can recognize crankshaft position.